Apparatuses and devices for measuring physiological parameters of organism or human body by utilizing various optical principles are gradually matured along with the advances in optical-electronic technologies. Generally, a non-invasive measurement can be accomplished by using an optical principle measuring technology, which offers important contributions and application values in medical or biological field, for it can effectively prevent infections or contagious diseases.
A conventional reflective oximeter is utilized to infiltrate an infrared light and a near infrared light into human body, and measure a light signal being returned. Later, a signal processor is utilized to calculate a blood oxygenation saturation by comparing absorption proportions of oxyhemoglobin (HbO2) and deoxyhemoglobin (Hb) for the infrared light and the near infrared light. Two major elements in the oximeter include one being a hardware measuring device for emitting and receiving the light signal and converting the light signal being received into an electrical signal; and another one being a display hardware and a software thereof in which blood oxygen values can be calculated. Since the measuring device often requires to be contacted to surfaces of human body, noises may be generated due to movements of the human body or changes in physiological conditions, which is prone to wrong blood oxygen values. Accordingly, the oximeter usually requires a software to filter out the noises, so as to ensure an accuracy of the value being read.